TY  - BOOK
AU  - Salle,Joseph La
AU  - Lefschetz,Solomon,1884-1972
TI  - Stability by Liapunov's direst method: with applications 
T2  - Mathematics in science and engineering
PY  - 1961///
CY  - New York
PB  - Academic Press
KW  - Stability
N1  - Includes bibliographical references : p. 131-132
ER  -